Plant Uptake Research Articles

Unveiling the impact of low-molecular-weight organic acids on enrofloxacin sorption in North China agricultural soil: Insights and implications

Low-molecular-weight organic acids (LMWOAs) play a crucial role as components of dissolved organic matter in soil, influencing the sorption/desorption, degradation, and plant uptake of diverse pollutants within the agricultural soil ecosystem. This study delves into the sorption behavior and mechanism of the fluoroquinolone antibiotic enrofloxacin (ENR) on agricultural soil in North China, focusing on the impact of LMWOAs. Through batch equilibrium experiments, we explored the sorption/desorption kinetics of ENR under varying conditions such as temperature, pH, ion strength, and ion type, with the addition of acetic acid, oxalic acid, and citric acid individually. Our findings reveal that the sorption and desorption kinetics of ENR—whether with or without LMWOAs—conformed well to the pseudo-second-order kinetic model (R2 ≥ 0.997). The presence of LMWOAs notably enhanced ENR sorption while impeding desorption in soil, with oxalic acid demonstrating the highest promotion effect followed by acetic acid and citric acid. Moreover, the sorption capacity and affinity of ENR decreased with rising solution pH, dropping from 96.8%-98.5% to 30.9%–34.4%. Acidic conditions favored ENR retention in soil, with inhibition of sorption escalating alongside increasing ionic strength. LMWOAs, soil solution pH, and coexisting ions emerge as pivotal factors shaping ENR sorption behavior. Furthermore, LMWOA presence intensified desorption hysteresis of ENR on soil, with a desorption hysteresis coefficient (HI) ≤ 0.124. These results suggest that LMWOAs restrict ENR mobility in the local soil environment, heightening the risk of its accumulation in soil and crops. This study offers valuable insights into the intricate interplay among LMWOAs, ENR sorption dynamics, and environmental outcomes, underscoring the importance of understanding such complexities in agricultural soil management.

Genome-wide identification and expression analysis of CASPL gene family in Zea mays (L.)

Casparian strip membrane domain proteins like (CASPL), exhibit profound associations with root development, stress responsiveness and mineral element uptake in plants. Nonetheless, a comprehensive bioinformatics analysis of the ZmCASPL gene family in maize remains unreported. In the study, we have identified 47 ZmCASPL members at the whole-genome level, systematically classifying them into six distinct groups. Furthermore, our analysis revealed that the same group of ZmCASPL contains similar gene structures and conserved motifs. Duplication events showed whole genome duplication (WGD) and tandem duplication (TD) contribute to the generation of the ZmCASPL gene family together in maize, but the former plays a more prominent role. Furthermore, we observed that most ZmCASPL genes contain MYB-binding sites (CAACCA), which are associated with the Casparian strip. Utilizing RNA-seq data, we found that ZmCASPL21 and ZmCASPL47 are specifically highly expressed only in the roots. This finding implies that ZmCASPL21 and ZmCASPL47 may be involved in the Casparian strip development. Additionally, RNA-seq analysis illuminated that drought, salt, heat, cold stresses, low nitrogen and phosphorus conditions, as well as pathogen infection, significantly impact the expression patterns of ZmCASPL genes. RT-qPCR revealed that ZmCASPL 5/13/25/44 genes showed different expression patterns under PEG and NaCl treatments. Collectively, these findings provide a robust theoretical foundation for further investigations into the functional roles of the ZmCASPL gene family in maize.

Effects of combined application of phosphorus and zinc on growth and physiological characteristics of apple rootstock M9-T337 seedlings (Malus domestica Borkh.)

BackgroundBalancing nutrient application is crucial for plant growth. However, excessive fertilizer use, especially imbalanced applications of macronutrients such as phosphate (P), can hinder plant uptake of micronutrients. Balanced P and zinc (Zn) are vital for apple yield and quality, and apple trees are highly sensitive to deficiencies in these nutrients. Therefore, this study was conducted in May 2022, employed a sand culture experiment to investigate the effects of varying P and Zn levels on the growth phenotype, photosynthetic capacity, antioxidant enzyme activity, sugar composition, endogenous hormone levels, and nutrient absorption and utilization of M9-T337 seedlings. Three levels of P (low, medium, high) and three levels of Zn (low, medium, high) were combined to create a total of nine distinct treatment.ResultsThe results indicate that combined P and Zn fertilization at various levels exerts either synergistic or antagonistic effects on the growth, nutrient absorption, and utilization of M9-T337 seedlings. Compared to low and medium levels of P, a combination of high P (4 mmol·L−1) and an adequate amount of Zn significantly enhanced plant growth, root system development, and the microstructure of leaves. Notably, seedlings treated with high P and low Zn (HPLZn) reached a height 1.54 times that of the medium P and medium Zn (MPMZn, control). Physiological indicators under HP conditions revealed significant increases in antioxidant enzyme activity, leaf water retention, photosynthetic pigment concentration, osmotic adjustment substances, and the contents of glucose, sucrose, fructose, endogenous hormones, as well as P and Zn accumulation in the leaves, compared to the control. However, an increase in Zn application led to a declining trend in these parameters. Specifically, the HPLZn treatment exhibited substantial increases in Net photosynthetic rate (Pn), Total chlorophyll (Chl a + b), glucose, fructose, sucrose, and Auxin(IAA), with increments of 7.12%, 27.32%, 11.40%, 23.20%, 16.67%, and 55.11%, respectively, compared to the control.ConclusionBased on the comprehensive ranking from principal component analysis, the combination of HP ( 4 mmol·L−1) and LZn (0.5 µmol·L−1) was found to be the most effective in enhancing the antioxidant capacity, sugar accumulation, osmotic regulation ability, photosynthetic capacity, endogenous hormone levels, as well as P and Zn nutrient absorption and utilization in M9-T337 seedlings.

Arsenic Uptake and Distribution in Green Pea Plants Under Arsenite and Arsenate Treatments

Soil arsenic (As) contamination is a global issue affecting regions worldwide. As in the soil is primarily present in inorganic forms, such as arsenite [As(III)] and arsenate [As(V)]. As is a microelement that is toxic to plants grown in As-contaminated soil. The aim of our study was to investigate the effects of increasing concentrations (0, 3, 10, 30, 90, and 270 mg kg−1) of As(III) and As(V) on the As content in green pea (Pisum sativum L.) and the distribution of As among different plant parts at four phenophases (the four-node stage, beginning of flowering, green ripening, and mature stage). Another aim was to determine the percentage of total soil As available to plants under different treatments. The results indicate that the developmental stage of the pea and treatment concentration significantly influence the distribution of As among plant organs. However, the differences between the effect of inorganic As forms were less pronounced. The amount of As absorbed by the whole test plant increased with higher treatment concentrations. In the case of As(III)-treatment, As amount in the whole plant increased from 0.170 µg to 7.31 µg (I. Phenophase); from 0.294 µg to 10.1 µg (II. Phenophase); from 0.435 µg to 31.6 µg (III. Phenophase); and from 0.697 µg to 36.1 µg (IV. Phenophase). As a result of As(V)-treatment, the whole plant’s As content increased from 0.170 µg to 8.94 µg (I. Phenophase); from 0.294 µg to 17.4 µg (II. Phenophase); from 0.435 µg to 29.7 µg (III. Phenophase); and from 0.697 µg to 58.5 µg (IV. Phenophase). The concentration of As accumulated by the plant also increased over time. The proportion of As absorbed by generative parts was much smaller than that absorbed by vegetative organs. The pea seeds generally accumulated less As (maximum 7%) than the pea pods (in some cases, this reached the 10%). As the total amount of As taken up by the plant increased, the proportion of As reaching the seeds generally decreased (from 5% to 0.3% in the case of As[III]-treatment, and from 5% to 0.1% in the case of As[V]-treatment). At treatment levels where the ability of the stem to retain As increased, a maximum of 1% of the total As absorbed by the plant was found in the seeds. Depending on the treatment, 3.82–5.69% [As(V)-treatments] and 3.9–6.07% [As(III)-treatments] of the total soil As were available to the plants. The difference in the ratio of the total As content to the soluble As content was more evident at higher treatment levels (≥30 mg kg−1). This value was typically lower for the As(V)-treatments.

Soil- and Foliar-Applied Silicon and Nitrogen Supply Affect Nutrient Uptake, Allocation, and Stoichiometry in Arabica Coffee Plants

ABSTRACT Silicon (Si) application may affect the plant response to nitrogen (N), possibly by changing the uptake, concentration, and partitioning of nutrients in plant tissues; however, this has not yet been proven in Arabica coffee plants. The effects of Si application methods [no Si, soil-applied soluble Si (168 mg Si L−1), and foliar-applied soluble Si (two application of 2 mg Si plant−1)] and N levels (0 and 80 mg N L−1) on biomass production and partitioning and uptake, partitioning, and stoichiometry of nutrients and Si in young Arabica coffee plants grown under greenhouse conditions were evaluated. Nitrogen fertilization increased the biomass production and uptake of all nutrients; however, reduced the concentrations of K, Ca, Mg, S, Mn, and Si in the leaves, Si in the stems, and K, Mg, and S in the roots of coffee plants as a dilution effect. In the presence of N, soil-applied Si increased the concentrations of Zn in the leaves and Ca and Si in the stems, the uptake of K, S, and Si, and the Si:N ratio. Foliar-applied Si increased the concentrations of N, P, K, and Zn in the leaves and Ca and Si in the stems, as well as the total uptake of K and Si and the Si:N ratio in coffee plants, being more evident in the N fertilization presence. This study unraveled that, especially when it was soil-applied, Si altered the nutrient uptake, allocation, and stoichiometric ratios with N, with a consequent increase in biomass production of young coffee plants fertilized with N.

Effects of NH4+-N: NO3−-N ratio on growth, nutrient uptake and production of blueberry (Vaccinium spp.) under soilless culture

Blueberry (Vaccinium corymbosum) is a small pulp shrub, which prefers to grow on a soilless culture. For soilless culture, nutritional management remains typically vital for blueberry production. However, the effect of different nutritional treatments on blueberry growth and production is largely unknown. This study was designed to investigate to formulate a specific nutritional treatment for blueberry. The results showed that NH4+-N: NO3−-N ratios significantly affected the growth, nutrient uptake, physiological characteristics, and flowering, as well as the fruiting characteristics of blueberry plants. The number of shoots and top projection area was increased considerably by 25:75 treatment. In contrast, 50:50 treatment promotes plant height, shoot length, and stem thickness, increasing chlorophyll contents, photosynthetic capacity, and P, Ca, and Mg in leaves. In contrast, 50:50 treatment promotes the flowering fruiting rate and prolongs the blueberry flowering period. The maximum soluble sugar contents were noted in 25:75, while maximum starch contents were reported in the 50:50 treatment. The treatments 100:0 and 75:25 promote early flowering and accelerate fruit set. Notably, NH4+-N: NO3−-N ratios; 50:50 treatment significantly encourages plant growth, nutrient uptake, chlorophyll contents, photosynthetic capacity, and fruit setting rate in blueberry plants. These findings suggested that NH4+-N: NO3−-N ratios 50:50 is the most appropriate treatment that significantly promotes vegetative growth and enhances production in blueberry plants. This study provides valuable information for improved blueberry production under a controlled environment.

Growth Rate and Nutrient Uptake of Stevia rebaudiana Bertoni as Influenced by Organic Manures in Laterite Soils of Kerala, India

A field experiment was conducted to understand the effect of organic manures on the crop growth rate (CGR), relative growth rate (RGR), and nutrient uptake of stevia (Stevia rebaudiana Bertoni) from April to August of 2022 and 2023 at the Agronomy farm, Department of Agronomy, College of Agriculture, Vellanikkara, Thrissur. The experiment was laid out in randomized block design (RBD) with 7 treatments replicated thrice which consisted of different levels of organic manures viz., three levels of farmyard manure (FYM@ 5, 10, 15 t ha­-1), three levels of vermicompost (VC@ 2.5, 5, 7.5 kg ha-1) and a control. The organic manure treatments significantly affected crop growth rate (CGR) and relative growth rate (RGR) in all the growth periods. The two-year pooled mean of CGR of stevia was significantly superior in FYM@15 t ha-1 over control in all the three growth periods i.e., at 0-30 DAP, 30-45 DAP and 45 DAP to harvest. Whereas, the two-year mean of RGR of stevia was found statistically higher in FYM@15 t ha-1 over control in the first two growth periods only. The organic manure treatments had a significant influence on the plant nutrient (NPK) uptake as well in both the years. The two-year pooled mean data regarding plant uptake of nitrogen and phosphorous was found significantly higher in FYM@15 t ha-1 over control whereas statistically higher pooled mean potassium uptake by stevia was found in VC@7.5 kg ha-1 over control. Overall, the higher levels of organic manure, especially FYM, significantly improve growth and nutrient uptake in stevia.

Inoculation with arbuscular mycorrhizal fungi improves plant biomass and nitrogen and phosphorus nutrients: a meta-analysis

Arbuscular mycorrhizal fungi (AMF) have profound effects on plant growth and nitrogen (N) and phosphorus (P) nutrition. However, a comprehensive evaluation of how plant N and P respond to AMF inoculation is still unavailable. Here, we complied data from 187 original researches and carried out a meta-analysis to assess the effects of AMF inoculation on plant growth and N and P nutrition. We observe overall positive effects of AMF inoculation on plant performance. The mean increases of plant biomass, N concentration, P concentration, N and P uptake of whole plant are 47%, 16%, 27%, 67%, and 105%, respectively. AMF inoculation induces more increases in plant concentrations and storage of P than N. Plant responses to AMF inoculation are substantially higher with single AMF species than with mixed AMF species, in laboratory experiments than in field experiments, and in legumes than in non-legumes. The response ratios of plant N and P nutrition are positively correlated with AMF colonization rate, N addition, P addition, and water condition, while unvaried with experiment duration. The biggest and smallest effect sizes of AMF inoculation on plant performance are observed in the application of nitrate and ammonium, respectively. Accordingly, this meta-analysis study clearly suggests that AMF inoculation improves both plant N and P nutrients and systematically clarifies the variation patterns in AMF effects with various biotic and abiotic factors. These findings highlight the important role of AMF inoculation in enhancing plant N and P resource acquisitions and provide useful references for evaluating the AMF functions under the future global changes.

Efficacy of nano urea in replacing conventional nitrogen application and its effect on fruit quality in strawberry

In a study conducted on strawberry cv. Winter Dawn, the combined application of nano urea and Azotobacter was investigated for its impact on quality and biochemical attributes under protected cultivation. The findings revealed a noteworthy response of strawberry plants to foliar nano applications compared to conventional soil application of urea. Despite the lower nitrogen dosage associated with nanoparticle supplementation, strawberries with nanoparticles exhibited significant improvements in qualitative and biochemical parameters. These results underscore the potential of urea nanoparticles as a viable nitrogen source, advocating for alternative approaches to nitrogen fertilization. By fine-tuning the dosage ratio, this strategy shows promise in fostering a more environmentally friendly, sustainable and modern method for cultivating strawberries. The enhanced quality and biochemical attributes observed in strawberries treated with nano urea highlight the efficacy of this innovative approach in optimizing plant growth and productivity. Furthermore, the utilization of nano urea in combination with Azotobacter demonstrates synergistic effects, potentially enhancing nutrient uptake and utilization efficiency in plants. This holistic approach improves crop quality and reduces the environmental impact associated with traditional fertilization methods. In conclusion, the findings of this study support the adoption of urea nanoparticles as a valuable tool in strawberry cultivation, offering a pathway towards sustainable agricultural practices. Future research efforts should focus on optimizing application protocols and assessing long-term effects to fully exploit the potential of nano-based fertilizers for strawberry.

Investigating the Interactive Effect of Arbuscular Mycorrhizal Fungi and Different Chelating Agents (EDTA and DTPA) with Different Plant Species on Phytoremediation of Contaminated Soil

Heavy metal (HM) contamination in soil poses a severe environmental threat, jeopardizing ecosystem health and potentially entering the food chain through plant uptake. Phytoremediation, a bioremediation technique utilizing plants to remove or immobilize contaminants, offers a sustainable and eco-friendly solution for HM remediation. This study investigated the interactive effects of arbuscular mycorrhizal fungi (AMF) and chelating agents (EDTA and DTPA) on the growth of maize (Zea mays L.) and alfalfa (Medicago sativa L.) cultivated in metal-contaminated soil and their impact on HM uptake by these plants. The findings revealed that AMF and chelating agents have complex interactive effects on plant growth and metal accumulation. Maize (Zea mays L.) shoot dry matter increased with AMF and chelating agents at lower concentrations. Both plants generally showed a significant (p ≤ 0.05) increase in shoot dry matter with amendments, with AMF × EDTA (10 mmol/kg) being the most effective for alfalfa. DTPA and EDTA generally reduced the DTPA-extractable metals in soil, suggesting potential for metal removal. However, the effects of AMF on metal availability were variable. Metal concentrations in maize (Zea mays L.) shoots increased with increasing DTPA and EDTA concentrations, while the effects of AMF were more complex. The alfalfa shoot metal content showed varied responses, with EDTA (5 mmol/kg) effectively reducing the metal uptake. In general, treatments involving chelating agents (DTPA and EDTA) tend to result in higher bioaccumulation factor (BF) values compared to the non-treated controls for most HMs in both plant species. Mycorrhizal fungi (AMF) treatment alone or in combination with chelating agents also showed that varied effects on HM uptake in both the alfalfa and maize treatments with chelating agents, especially at higher concentrations, generally promoted the greater translocation of HMs in both plant species. Both alfalfa and maize responded differently to treatments, with some treatments showing higher translocation factor (TF) values for certain HMs in one species compared to the other. Mycorrhizal fungi (AMF) treatment alone or in combination with chelating agents also showed varied effects on HM uptake and translocation in both alfalfa and maize. Further research is required to optimize remediation strategies that balance plant health and metal mobilization.

Synergy between Arbuscular Mycorrhizal Fungi and Rhizosphere Bacterial Communities Increases the Utilization of Insoluble Phosphorus and Potassium in the Soil by Maize.

Arbuscular mycorrhizal (AM) fungi can enhance plant uptake of phosphorus (P) and potassium (K), but it is not yet clear whether rhizosphere bacteria can enhance the ability of AM fungi to acquire insoluble P and K from the soil. Here, pot experiments confirmed that AM fungus-promoted insoluble P and K uptake by plants requires rhizosphere bacteria. The changes of rhizosphere bacterial communities associated with AM fungi were explored by 16S rRNA amplicon sequencing and metagenomic sequencing. Five core bacteria genera identified were involved in P and K cycles. Synthetic community (SynCom) inoculation revealed that SynCom increased soil available P and K and its coinoculation with AM fungi increased P and K concentration in the plants. This study revealed that AM fungi interact with rhizosphere bacteria and promote insoluble P and K acquisition, which provided a foundation for the application of AM fungal-bacterial biofertilizers and was beneficial for the sustainable development of agriculture.

Iodine-Enriched Urea Reduces Volatilization and Improves Nitrogen Uptake in Maize Plants

Urea is the primary source of nitrogen (N) used in agriculture. However, it has a high N loss potential through volatilization. Various mechanisms can be employed to reduce N volatilization losses by inhibiting urease. When added to urea, iodine (I) has high potential for this purpose. Thus, this study aimed to determine whether adding I to urea reduces volatilization losses and increases N uptake in maize plants. Maize plants were cultivated in greenhouse conditions for 36 days. Urea treatments were applied at 15 days of testing, including iodine-enriched urea, conventional urea, and no urea application. Additionally, a study concerning N volatilization from urea was conducted using the same treatments under the same environmental conditions. Iodine was incorporated and adhered to urea, at an I concentration of 0.2%, using potassium iodate (KIO3). Under controlled conditions and over a short period of time, it was observed that the application of iodine-enriched urea increased the chlorophyll b content, root N accumulation, and total N accumulation in maize plants compared with conventional urea. Moreover, iodine-enriched urea reduced N losses from volatilization by 11% compared with conventional urea. The reduction in N volatilization correlated positively with the increased chlorophyll b, total chlorophyll, root N accumulation, and total N accumulation favored by the iodine-enriched urea treatment. Our findings demonstrated that adding I to urea is an efficient and promising strategy to reduce N losses and increase N uptake in plants.

Synchronous and efficient removal of carbon, nitrogen, and phosphorus from actual rural sewage by composite wetlands enhanced with functional fillers

A composite wetland (CECW) was constructed by introducing P-adsorption filler (EPAF) and activated sludge into traditional wetlands for treating actual sewage. The results showed that EPAF improved P removal through physico-chemical adsorption, and it could be stably regenerated after adsorption saturation without potential risks. Meanwhile, zeolite promoted NH4+-N reduction in sewage by cation exchange. In addition, simultaneous biological removal of carbon, nitrogen, and phosphorus was achieved through nitrification, denitrification, anammox, and aerobic P-accumulation processes induced by Nitrobacter, Proteus Hauser, Candidatus Paracaedibacter, and Brevundimonas. Under the coupling of filler interception/adsorption, microbial assimilation/transformation, flocculation, and plant uptake, CECW obtained the removal rates of 93.22 %, 85.75 %, 91.80 %, 95.38 %, 97.07 %, and 78.05 % for turbidity, TN, NH4+-N, TP, PO43−-P, and TCOD, which met the Class 1A standard (GB18918-2002). Therefore, the experiment systematically investigated the effects and mechanism of CECW in treating actual sewage, which could provide reference for rural sewage treatment and sludge utilization.

Soil Phosphorus Transport in Response to Climate Change at Mid‐High Latitudes Under Intensive Agriculture

ABSTRACTPhosphorus (P) is an important soil element for sustaining plant growth and the integrity of terrestrial ecosystems, and the soil P cycle is strongly influenced by climate change and agricultural activities. However, little is known about how soil P has evolved with climate change and intensive agriculture at mid‐high latitudes, where the soil P cycle is sensitive to climate change. To answer this question, an ecohydrological model (EcoHAT‐P) driven by remote sensing data was used in this study to calculate soil P concentration and loss and was calibrated and validated using 272 soil samples collected in the Sanjiang Plain, a typical mid‐high latitude region with a long history of strong agricultural activity. Soil P concentration and loss, and plant uptake of soil P, were analyzed for the years 2000–2019 and 2020–2040. The results showed that soil total P, soil P loss, and plant P uptake all increased under intensive agriculture. The soil P cycle at mid‐high latitudes was more sensitive to temperature than to precipitation. Increased temperature would increase soil P loss and plant P uptake by 93.94% and 8.16%, respectively, and soil legacy P from intensive agriculture would become the main source even if external P inputs were eliminated. The results highlight the evolution of soil P transport at mid‐high latitudes and clarify the response of soil P cycle to climate change under intensive agriculture.

Plant functional type and peat properties determine elemental transfer in boreal mire vegetation

Uptake of elements into plants is an integral part of many environmental impact assessments. Typically, the plant uptake is determined using an empirical soil-to-plant transfer factor (CR). The elemental concentrations in plants are expected to vary with plant species and plant functional type (PFT), but also according to soil and element properties. Specifically, the uptake of essential elements is regulated, and likely less related to soil concentrations than the uptake of non-essential elements. In this study, the impact of PFT, species and environmental factors on the CR of mire plants was tested. The plants included in the study were four common boreal peatland species (Andromeda polifolia, Vaccinium oxycoccus, Eriophorum vaginatum and Carex rostrata) sampled from 40 minerogenic mires along an age gradient.The results show that while plant species and PFT (heathers and sedges) are the main determinants of the CR value, also environmental factors, such as peat C:N ratio, are important. Further, concentrations of essential elements in plants were only weakly correlated to peat concentrations, whereas the correlation was stronger for non-essential elements and elements utilized at trace amounts.The results of this study verify that CR values may vary substantially between peatland plant species and PFTs. Further, the results suggest that it is relevant to include effects of PFTs on CR and among-species variation in environmental impact assessments. This is because the PFT may have a large impact on the exposure pathways to humans, which could, for example, be berries or animal feed, and also due to the uncertainties of the composition of the future vegetation communities. Since CR varies systematically with several soil properties, there may be potential for adjusting the CR values for expected environmental changes, and thereby reduce the uncertainties of empirical CR values determined from a broad range of environmental conditions.

Nitrogen Fertilization in Snap Bean Following a Legume in the Sandy Soils of North Florida

Despite being a legume, snap bean (Phaseolus vulgaris L.) lacks nodulation genes, restricting its ability for nitrogen (N) fixation through rhizobia, making N fertilization essential for maximizing yields. However, conventional fertilizer application may lead to N losses due to a lack of synchronization between plant uptake and N availability. A promising option could be controlled-release fertilizers (CRFs), which can be custom-formulated to synchronize nutrient release with plant growth needs, promoting efficient resource use. Field studies were conducted at the North Florida Research and Education Center-Suwannee Valley (NFREC-SV) in Live Oak, FL, during the spring of 2021 and 2022. The experiments also investigated broadcasting and banding application methods of the University of Florida’s recommended N rate (112 kg·ha−1). The experimental design comprised 10 treatments, including five N rates (0, 56, 112, 168, and 224 kg·ha−1 N) and two fertilizer sources (ammonium nitrate and CRF), applied to ‘Caprice’ in a randomized complete block design with four replications. Results showed a significant yield improvement with N fertilization vs. the zero-N control. However, no yield increase was observed beyond 56 kg·ha−1. This finding could be due to the residual N from a preceding peanut crop rotation in both years. No notable variation in quality metrics (pod length and width) occurred above the 56 kg·ha−1 threshold. The results also revealed that the choice between conventional or CRF did not exert any statistically significant differences in snap bean yield. In addition, fertilizer broadcast and banding treatments yielded the same results.

Influence of light intensity on the responses of seedlings of neotropical tree species to nitrogen source

Light intensity plays a crucial role in N uptake and assimilation in plants, but its interaction with different N sources is overlooked. Considering the high energy required for N assimilation, it is hypothesised that low light is critical for the seedling development with both N sources, but with increased light intensity, growing with nitrate (NO3-) becomes favourable in relation to ammonium (NH4+). Seedlings of Cecropia pachystachya (pioneer), Guarea kunthiana (shade-tolerant, understory) and Cariniana estrellensis (shade-tolerant, canopy) were grown in hydroponic medium with NO3- or NH4+ as the sole N source and subjected to low (LL) or high light (HL) for 60 days. All three species showed a decrease in growth when cultivated with NH4+, compared to NO3-, under HL, but not under LL. The decrease in biomass reached 54% in C. pachystachya, 36% in G. kunthiana and 26% in C. estrellensis. Growth reduction was associated with stomatal limitation of photosynthesis and reduced leaf area in C. pachystachya, and with non-stomatal limitation of photosynthesis and oxidative stress in G. kunthiana. Cation uptake was negatively affected by NH4+ in all species. Cariniana estrellensis showed no photosynthetic limitation and showed a higher tolerance to NH4+ under HL in terms of nutrient content. In conclusion, neither N source significantly favors seedling development under LL, while NH4+ is considerably more unfavorable for seedling development than NO3- under HL.

Investigating plasma activated water as a sustainable treatment for improving growth and nutrient uptake in maize and pea plant

In this study, an atmospheric pressure air plasma jet (APAPJ) was employed to generate plasma-activated water (PAW), which was applied to treat maize (monocot) and pea (dicot) seeds for evaluating its influence. This research explored APAPJ diagnostics by varying the air feed rate as 1, 2, and 3 liter per minute (Lpm) through current-voltage characterization, optical emission spectroscopy, electron temperature and density, nitrogen metastable state density, and rotational and vibrational temperature of the plasma. Additionally, various reactive oxygen and nitrogen species (RONS) formed and physicochemical properties of PAW were analyzed by varying plasma treatment time from 0 to 8 min. Furthermore, the water uptake of maize (Zea mays) and pea (Pisum sativum) seeds were examined by the measurement of the contact angle. Results indicated that APAPJ has the capacity of fostering germination, growth, chlorophyll, phosphorus, nitrite, nitrate, ammonium ion and leaf area in plants significantly with an optimized 6 min treated PAW for maize and 2 min treated PAW for peas. Among various categories, seeds soaked in PAW and irrigated with PAW exhibited the most outstanding result in germination and plant growth. Non-thermal plasma showed promising green methods for enhancing plant growth and boosting nutrient content.

Structure-Dependent uptake and metabolism of Tire additives Benzothiazoles in carrot plant

Tire additives, such as benzothiazole and its derivatives (collectively called BTs), are large-volume chemicals that are constantly emitted into agricultural environment via tire-road wearing and other actions. The potential accumulation of BTs in food crops depends largely on their metabolism in plants, which is poorly understood. Herein, we evaluated uptake and metabolism of six BTs in carrot callus and intact carrot plants to understand their structure-specific metabolism. All BTs were readily taken up by carrot roots, with their root concentration factors (RCF) ranging from 1.66 ± 0.01 to 2.95 ± 0.05. Although the tested BTs exhibited poor upward translocation from root to leaves (translocation factors < 1), the translocation factors of 2-methylbenzothiazole (0.79) and 2-aminobenzothiazole (0.65) were significantly higher than that of 2-methylbenzothiazole (0.18) and 2-(methylthio)benzothiazole (0.22). These results indicated the structure-dependent uptake and translocation of BTs in carrot. Correlation analysis between log Kow and log RCF or TF revealed that the hydrophobicity of BTs predominantly affected their root uptake and acropetal translocation in carrots. With the aid of high-resolution mass spectrometry, a total of 18 novel metabolites of BTs were tentatively identified, suggesting that BT compounds can be metabolized by carrot callus. The proposed metabolites of BTs include four hydroxylated products, one demethylated product, five glycosylated products and eight amino acid conjugated products, revealing that glycosylation and amino acid conjugation were the dominant transformation pathways for BT metabolism in carrot. However, the detected species of metabolites for six BTs varied distinctly, indicating structure-specific metabolism of BTs in plants. The findings of this study improve our understanding of structure-dependent fate and transformation of BTs in plants. Since BTs metabolites in food crops could present an unintended exposure route to consumers, the structure-specific differences of BTs uptake, metabolism and accumulation in plants must be considered when addressing human dietary exposure risks.

Response to Addition of Lighting Duration and Electrical Induction in Lettuce (Lactuca sativa L.) Plant on the Uptake of Nitrogen, Phosphors, Potassium and Yield

Background: The impact of excessive use of chemical fertilizers and pesticides causes problems of land degradation, low fertility levels and reduced cation exchange capacity. To increase nutrient uptake and yield of lettuce plants, cultivation techniques using induction and additional lighting are needed. The aim is to increase nutrient absorption and plant yields. Methods: The research design used a split plot with Factorial Randomized Groups. Factor 1 Lighting duration (P) for 4 and 8 hours per day and Factor 2, induction with DC (Direct Current) current (S). Induction 1 time per day (S1); The treatment in this study was repeated 4 times. Induction 2 times per day (S2) and Induction 3 times per day (S3). Result: The combination P2S2 showed good results regarding the uptake of Nitrogen (20.1 Kg.Ha-1), Phosphorus (2.71 Kg.Ha-1) and Potassium (67.23 Kg.Ha-1) in plant leaves. The P1S2 treatment showed a leaf area of (1652.19 cm2). The adding 4 hours of light and an induction interval of 2 times per day gave good results on the uptake of Nitrogen, Phosphorus and Potassium in the leaf of lettuce plants.